1. Field of the Invention
This invention relates to printing systems in general, and more particularly to a system including a printer driven from a memory in which stored constant and variable data are automatically and selectively merged during printing.
2. Description of the Prior Art
The above-referenced, copending patent application Ser. No. 595,840 describes a system in which one portion of a memory is loaded with fixed data, such as text codes and control codes for printing the constant portions of a repetitive form letter, while the remainder of the memory is loaded with variables to be included in one or more of the letters to be printed according to the form letter. As an example, a letter of congratulations could be sent to fifty graduates of a marketing training class by loading the constant, congratulatory text into one portion of the memory of the names and addresses of the graduates into another portion of the memory. SWITCH codes are used to indicate the locations in the form letter requiring the addition of a field from the variables to personalize the form letters. For example, after the date in the form letter, a SWITCH code may be utilized to read variables including the name and inside address of the addressee until a SWITCH code at the end of the inside address in the variables causes reading of the memory to switch back to the "Dear" in the form letter. After the "Dear" in the form letter, a SWITCH code would again switch reading of the memory contents back to the variables for the name of the addressee, which in the variables, would be followed by another SWITCH code to cause playout of the form letter to continue.
One of the problems with the above described system is that no practical provision is included for the printing of envelopes to be associated with the personalized form letters other than the obvious solution of limiting the variables in the letter to an inside address that can also be used for addressing the envelopes. This solution had the problem of requiring the salutation as well as the remainder of the text to use only form text, for example, "Dear Marketing Training Graduate", since inclusion of additional variable fields to further personalize the letter could not be used on the envelope. Additional personalizing fields can be included if the system is set up to tab the print carrier off of the envelope to print the variable fields not pertinent to the envelope, but this causes unnecessary time delays for printing this extraneous data as well as additional printer wear.
Thus, previous solutions to the problem of printing envelopes along with the form letters have required (1) a lower degree of personalization of the letters than is desirable, or (2) the additional printing of the remainder of the record not pertinent to the envelope. Thus, it would be desirable to employ, for printing of both form letters and envelopes, a single record including, without repetition, those fields needed for both the form letter and the form envelope with means operable to skip particular fields of the record that are not to be included on the envelope and, additionally, to skip other fields of the record that are not to be included with the letter. Further, it would be advantageous to print all copies of a particular letter during the same operation, followed by an envelope, so that distribution of the letters can begin at the start of printing of the next succeeding letter which utilizes a different record of variables.